Media regulator Ofcom has ruled that Celebrity Big Brother breached its code of conduct over the race row which dogged the series in January.

The watchdog found that Channel 4 made "serious editorial misjudgements" in its handling of the incidents involving Indian actress Shilpa Shetty.

Channel 4 has been ordered to broadcast a summary of Ofcom's findings at the start of series eight next week.

The channel apologised again and said it accepted Ofcom's ruling.

The show's creator, Endemol, said it also accepted Ofcom's findings and "sincerely regretted the level of offence caused by events in this series".

"We are grateful to Ofcom for recognising that the events of this series were in no way engineered or manufactured," the company added in a statement.

This year's celebrity version attracted a record 45,000 complaints to Ofcom.

Jade Goody was at the centre of the row

Channel 4 will have to broadcast Ofcom's findings ahead of three of its programmes - the first show of the new Big Brother series on 30 May, the first re-versioned show the following morning and the first eviction show.

Ofcom said that its starting point was not that material which is potentially offensive or harmful had been transmitted but whether such material had been appropriately handled by Channel Four.

Ofcom singled out three occasions where it felt the channel had failed.

One was where Jade Goody referred to Shetty as "Shilpa Poppadom", the second was Lloyd telling Shetty in foul language that she should go home.

Andy Duncan should now apologise to Shilpa Shetty

Keith Vaz MP

The third centred on an argument over Shetty cooking a chicken - Lloyd and O'Meara were both seen making offensive comments about Indian cooking.

In unseen footage from the show, Goody, O'Meara, Lloyd and Goody's boyfriend, Jack Tweed, were seen making up a limerick about Shetty in which they joked about using a word which they said rhymed with "tacky".

The group were reprimanded by Channel 4 for these remarks, which occurred before two of the incidents Ofcom singled out.

Shetty eventually won the contest and insisted ringleader Jade Goody "didn't mean to be racist".

Culture secretary Tessa Jowell has welcomed Ofcom's decision.

"Errors of judgment were made which Channel 4 has acknowledged. I therefore welcome the measures that they have taken to ensure proper and rigorous oversight. We will be watching very closely to ensure that these have the desired effect."

Call for resignation

Channel 4 Chairman Luke Johnson said he felt the sanction imposed was "proportionate given Ofcom's ruling that the breaches were not deliberate and that the channel did not act recklessly".

The channel conducted its own review and will now:

Appoint its first viewers' editor and launch a right to reply programme.

Introduce a new written intervention policy which spells out how the show will tackle seriously offensive language or behaviour.

Appoint a senior welfare officer whose sole task is to observe housemates and to advise producers of any concerns.

"It is essential that broadcasters are able to air challenging and controversial material but in doing so they must have effective compliance procedures in place and must exercise their editorial duties responsibly," said Ofcom's chief executive, Ed Richards.

Labour MP Keith Vaz, who led protests in Parliament over the issue and introduced Shetty to Tony Blair, has called for Channel Four chief executive Andy Duncan to resign.

"I welcome the adjudication by Ofcom. This is a vindication of the huge number of complaints that were made by viewers," he said.

"Andy Duncan should now apologise to Shilpa Shetty and realise that the contempt that was shown by them during this whole episode, in my view and that of many of the viewers who complained, now merits his resignation," he added.

The Commission for Racial Equality said it would be keeping a close eye on the new series of Big Brother.

"We will be monitoring it carefully to ensure that such disgraceful behaviour is not repeated," a spokesman said.